(ios) Fix foreground notifications not being displayed after calling grantPermission when permissions haven't been previously granted

[vneenz]

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Documentation changes
• Other... Please describe:

PR Checklist

Please check your PR fulfills the following requirements:

Bugfixes:

• Regression testing has been carried out using the example project to ensure the intended bug is fixed and no regression bugs have been inadvertently introduced.

What is the purpose of this PR?

Currently, calling grantPermission on ios while permissions have not been granted will cause received foreground notifications (notifications with "notification_foreground": "true") to not be displayed until app is restarted. This seems to happen because the grantPermission function changes the notification center delegate if called and permissions have not been already granted:

cordova-plugin-firebasex/src/ios/FirebasePlugin.m

Lines 303 to 310 in ab66059

	[self _hasPermission:^(BOOL enabled) {
	@try {
	if(enabled){
	NSString* message = @"Permission is already granted - call hasPermission() to check before calling grantPermission()";
	CDVPluginResult *pluginResult = [CDVPluginResult resultWithStatus:CDVCommandStatus_ERROR messageAsString:message];
	[self.commandDelegate sendPluginResult:pluginResult callbackId:command.callbackId];
	}else{
	[UNUserNotificationCenter currentNotificationCenter].delegate = (id<UNUserNotificationCenterDelegate> _Nullable) self;

Meanwhile the completionHandler for the permission request never sets this back to the original value

cordova-plugin-firebasex/src/ios/FirebasePlugin.m

Lines 321 to 331 in ab66059

	completionHandler:^(BOOL granted, NSError * _Nullable error) {
	@try {
	NSLog(@"requestAuthorizationWithOptions: granted=%@", granted ? @"YES" : @"NO");
	if (error == nil && granted) {
	[self registerForRemoteNotifications];
	}
	[self handleBoolResultWithPotentialError:error command:command result:granted];
	}@catch (NSException *exception) {
	[self handlePluginExceptionWithContext:exception :command];
	}

The notification center delegate is first set here during app startup:

cordova-plugin-firebasex/src/ios/AppDelegate+FirebasePlugin.m

Line 80 in ab66059

[UNUserNotificationCenter currentNotificationCenter].delegate = self;

The fix included in this PR simply sets the notification center delegate back to the AppDelegate if permissions were granted successfully.

Does this PR introduce a breaking change?

• Yes
• No

What testing has been done on the changes in the PR?

This change has been tested in a production app

What testing has been done on existing functionality?

Other information